With increasing development of digitalized technologies, a variety of digital products are designed in views of convenience and user-friendliness. Nowadays, many electrical appliances are widely used with personal computers due to the amazing power of the personal computers. The personal computers are developed to meet a so-called “plug and play” requirement to increase convenience and operating efficiency of the personal computers. For example, an interface card complying with the specification of a peripheral component interconnect (PCI) interface or a PCI Express (PCIe) interface can be installed in the computer system to implement some functions of for example displaying images, producing sound effects, processing video data or connecting with network. When an operating system, operated by the computer system, such as Windows, Linux, Mac and the like detects the presence of an interface card and a corresponding driver is loaded, the interface card is enabled. It is of course that the driver should be previously installed in the computer system by for example loading the driver from a storage medium.
For meeting the “plug and play” requirement, a universal serial bus (USB) interface is utilized. That is, an external device is communicated with the computer system via the USB interface in hot-plugging and unplugging manners without shutting down the computer system. The common USB external devices include mice, keyboards, printers, flash drives, digital cameras and the like. The USB external devices further include a variety of memory cards in different formats such as SD, MS, CF or SM memory cards. By means of corresponding card readers, the data stored in the memory cards can be read by the computer system. When the USB external devices such as mice or keyboards are electrically connected to the USB interfaces of the personal computer, the operating system of the personal computer may recognize the presence of these USB external devices. If the operating system supports the drivers of these USB external devices, the USB external devices will be activated when being plugged into the USB interfaces of the personal computer. It is of course that the driver should be previously installed in the computer system to execute specified application programs for the USB external devices.
Nowadays, many products are developed according to embedded system technologies. Since the products are characterized by special functions, the embedded systems of these products are designed in views of certain functions. In contrast, the operating system of the personal computer can support a broader application range. For examples, mobile computing devices such as mobile phones, personal digital assistants (PDAs) or global positioning system (GPS), handheld game consoles and set-top boxes are typical products fabricated according to embedded system technologies. As known, the embedded products have limited memory capacity and specified operating systems are needed. If no driver supporting the operating system has been previously installed in the embedded products, the external devices as described above may fail to be normally operated with the embedded products. In comparison with the personal computer, it is harder to install the driver of the external device in the embedded product and thus the working efficiency of the embedded product cannot be easily increased.
An exemplary embedded product includes a portable media player (PMP). With increasing development of software for the portable media player, it is impossible to pre-install all drivers and application programs in the portable media player. If a corresponding adapter such as a TV adapter or a network adapter is plugged into an interface device of the portable media player, the portable media player may execute the functions of playing TV programs or connecting to the network. Unfortunately, if the adapter is not recognized by the portable media player or no driver has been previously installed, the functions of playing TV programs or connecting to the network cannot be successfully executed. Moreover, if a notebook computer without an optical disc drive is used, the driver for a CardBus wireless network card may cannot be installed via an optical disc drive or downloaded via the network. Under this circumstance, the wireless network card is not recognized or supported by the operating system of the notebook computer and thus fails to be normally operated.
In other words, when the interface device of an embedded product, a computer system or a similar backend host is communicated with an external device, the functions of the external devices fail to be controlled by the backend host in some instances. For example, these instances occur when the external device is not recognized by the backend host, no driver for the external device has been installed in the backend host, and the driver for the external device fails to be downloaded to the backend host.
In views of the above-described disadvantages resulted from the prior art, the applicant keeps on carving unflaggingly to develop an external device for use with a backend host according to the present invention through wholehearted experience and research.